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MARK DOMBROFF, AVIATION ATTORNEY: In that particular instance, there was no warning given to the pilots or by the pilots to air-traffic control. Communication simply stopped. They passed the word on to -- from air-traffic control to their authorities and fighter jets were scrambled. They observed the aircraft basically crash as the engines ran out of fuel.

The ultimate determination was there was a decompression. They never determined whether it was an explosive decompression, all at once, or it was an insidious decompression that essentially put the people to sleep.

But we know the aircraft continued to fly to the Dakotas where it ultimately crashed. I suppose one could draw parallels to this particular situation.

ASHLEIGH BANFIELD, CNN ANCHOR: Let me sort of break that out a little further, just in the notion that when these people took off, this was a red-eye flight, and as we all know, in a redeye flight one of the first things you do is bed down and get ready to go to sleep.

So, Colonel Kay, is it so implausible that a slow decompression could have happened with no one on board ever knowing, hence no distress call, no need for the oxygen, and the oxygen doesn't deploy until you're quite high up in these particular airplanes. Is it so implausible that a lot of sleeping passengers became hypoxic without even knowing it?

MICHAEL KAY, CNN AVIATION ANALYST: We can't rule it out, but here are some considerations.

In order to have some sort of decompression, you've got to have the structural integrity of the airplane compromised in some way. The first action is for the pilots to put on the oxygen. Once they've got the oxygen on, they're fine, OK?

Now, with some compromise of the structural integrity of the airplane, there should normally be some indicator on a central warning panel in the cockpit to let them know that depressurization is occurring, OK? Now, the cabin is pressurized to 8,000 feet. They normally transit around 35,000 feet. If there is a depressurization that's gone on, they will then look to bring the aircraft below 10,000 feet for the hypoxia, why did the aircraft then climb again?

Why did they not bring the aircraft back to an airfield? Why was an emergency not declared? So there are a number of reasons to sort of say, yes, it could have happened --

BANFIELD: And then again --

KAY: -- but if it did happen, why did it --

BANFIELD: And that seems to be with every single theory, which is so maddening about this.

And, David Soucie, you and I have had a lot of conversations off-air about the potential dangers of having a cargo of lithium batteries and on board this flight there was a cargo of lithium batteries. Can you just explain simply for our viewers the dangers of the fire, the dangers of the gases, the kinds of gases that are used to put out the fires, and why this may add to this mystery?

DAVID SOUCIE, CNN SAFETY ANALYST: Well, in 2010, a UPS flight crashed and it was decided and found out the hat lithium batteries on board were what caused that accident.

And since that time, the halon fire extinguishers, automatic fire extinguishers are the commonplace in these aircraft as far as putting the fires out. Now --

BANFIELD: Let me just stop you there, David. Halon being a gas that's emitted that puts the fire out, correct?

SOUCIE: In essence, it displaces the oxygen away from the burning source.

Now, in the aircraft of UPS, what happened there is the flames continues to intensify to a point at which it damaged the structural integrity of the aircraft and caused the craft.

Since then, the halon would turn off or extinguish the flames of the lithium batteries, but it would not stop the heat. It wouldn't stop the escape of gases. In a fire, those gases, those dangerous, deadly gases are burned away with the flames. So it's the heat that causes the structural damage.

In this case, if the fire had been extinguished yet those batteries continued to heat and put off gases, we're talking hydrogen chloride and sulfuric acid in very dense amounts put into the air in that aircraft.

Now, I hate to speculate too far on this, but the fact is there is historical data that talks about this, and there is 114 different incidents, reported incidents, of lithium batteries being loaded onto or removed from aircraft that have actually had these fires happen. And so that's -- it's not a new thing. This is something that's been going on for a long time.

In the United States, you can't put that quantity of batteries, or even any lithium batteries, in any kind of quantity of the cargo compartments when there's passengers on board. It's strictly done through cargo aircraft. So that's where I'm concerned about this point is that there's a history of it, there's a probability of it and it would explain the incapacitation of the crew and members on -- passengers.

BANFIELD: So just with 10 seconds left, you're saying that the hydrochloric acid and the sulfuric acid that's emitted after the halon doesn't allow it to burn off from the plane would leach somehow into the plane and that would incapacitate everyone, and it would be another ghost flight.

Is that what you're saying?

SOUCIE: Exactly.

BANFIELD: OK. Well, thank you for that, and thank you, all of you, Mark Dombroff, David Soucie, and Michael Kay, just invaluable information.

Stay with me, folks, because with all these theories about what happened to this plane, there are the hard realities, the hard realities of trying to physically locate any piece of it. Is searching by air even relevant anymore? Should different types of search technology be introduced into this mystery?

A look at all these questions and why they may be valid or not, coming up.

(COMMERCIAL BREAK)

BANFIELD: If you don't find something that you're looking for, you have a couple of choices. You can look harder and you can look somewhere else, or you can just choose to live without it.

And that sounds pretty simple, but an airliner filled with 239 people is certainly not like one of your prized possessions. For the leaders of the search for MH-370, the choices get a lot more complicated with every dead-end they encounter, and CNN's Jean Casarez explains.

(BEGIN VIDEOTAPE)

TONY ABBOTT, AUSTRALIAN PRIME MINISTER: Australia will not rest until we have done everything we humanly can to get to the bottom of this mystery.

JEAN CASAREZ, CNN CORRESPONDENT: It is a mystery no closer to being solved. The Bluefin-21 autonomous underwater vehicle has searched the targeted area with no luck. Experts are preparing for the next phase of the recovery effort.

HISHAMMUDDIN HUSSEIN, MALAYSIAN TRANSPORTATION MINISTER: This requires more deep-sea assets. This requires more, probably, Bluefin-21s. This requires probably submersibles that will be very, very expensive.

But again, I am heartened by the fact that there are so many people out there who are interested in coming on board.

CASAREZ: With additional countries coming on to help, coordination worldwide could be tricky.

SOUCIE: It would simply complicate and extend the process. It's a very bad mistake in my estimation.

FABIEN COUSTEAU, OCEAN EXPLORER: There needs to be a spearhead, so to speak, a mission control, if you like, that organizes all these assets. Otherwise, we may be seeing different entities covering the same ground and, therefore, being inefficient and wasting a lot of time and money.

CASAREZ: Ocean explorer Fabien Cousteau says it's about time they add assets and include submarines.

COUSTEAU: There's a big difference between a robot or an ROV and AUV versus having people down below searching with their own two eyes. There's only so much a sonar can do, visually speaking. Now, that said, the area they're searching may not be the right area.

CASAREZ: That's why searchers may need to revisit even the most fundamental data, which could mean yet another look at the Inmarsat data used to establish the search zone.

HUSSEIN: It's a matter of looking at all the data, whether it's satellite, whether it's radar. And that is very important as we chart our next course.

CASAREZ: One area that could be eliminated is search by air. Is it still relevant?

SOUCIE: If that air search finds even the slightest little thing, the slightest little piece from that aircraft, it would give them some closure on what's going on.

COUSTEAU: It's an extraordinary difficult decision to make, and on a daily basis, at that.

I wouldn't want to be the one having to orchestrate this extraordinarily complex search.

CASAREZ: Jean Casarez, CNN.

(END VIDEOTAPE)

BANFIELD: Is it time to send in reinforcements for the lonely undersea robot that's now on its 12th dive in depths that it was never actually designed to reach.

I'm joined again by our aviation analyst Colonel Michael Kay and by ocean explorer and expedition specialist Christine Dennison. And, Christine, that's a perfect question for you. Every time I see the Bluefin-21. I hear it's the Cadillac of machinery, and yet it's tiny and I wonder if it's big enough for this incredibly big job.

CHRISTINE DENNISON, EXPEDITION LOGISTICS SPECIALIST: It is. It's been a monumental effort that they've sort of been putting this machine through. And it's fair enough to say that I think it's done a great job. It can do this.

Aside from the Bluefin-21, I would say that they can bring in the Remus, which is a ROV which can go to depths of 6,000 meters. Bring in more AUVs. I'm a big proponent that, at this point, you need more sonar, sonar, sonar. So you do need and you can work with additional AUVs, expanding the search area.

One thing I am totally against is manned submersibles. They don't make sense. You do not put a manned submersible down at these depths when you have very limited battery time.

Visuals, what if this wreck, what if wreckage is embedded in sand? Visuals are going to pick that up. You need cameras. You need sonar. You need the ability to really sort of get down there and take the visuals, which cameras can do. People are not going to have the same abilities nor are these submersibles.

BANFIELD: When you mention manned submersibles and we look at these remarkable robots on the screen right now, oftentimes what people think about when you talk about manned submersibles are submarines.

And some of the finest submarine technology in the world is in the hands of the Americans and a lot of people keep asking why are we not dispatching every single submarine we have into this effort?

And, Colonel Michael Kay, there's a good answer

KAY: There is a good answer. The submarine force not just for the Americans, the Russians, the U.K., it's a strategic asset. It's also a covert strategic asset. What makes submarines so effective is the fact that you don't know where they are.

Now I thought it was unusual that we announced the HMS Tireless was coming onto the scene. Remember the British submarine? That's a hunter. That carries cruise missiles, the likes that we used to launch on Iraq when we went in there in 2003.

It's not good to let the world know where your strategic covert assets are. So I think that it's plausible that there will be submarines assisting with this search. But if you're government and you want to protect national interests and you don't want to let the Russians know where your submarines are, you'll be doing it under the radar rather than letting the world know.

BANFIELD: And truly, Christine, do we even know what the technologies are on the submarine forces around the world right now, Americans aside? DENNISON: No. I agree with that, but we don't. I know that, to date, as of this morning, the U.S. announced that we've spent $11.4 million to date on this plane search.

So that's a lot of money for just one of the players of the international group that's working on this to be putting in there. I don't think that we will be privy to a lot of the covert or secret machines that we may have available to us (Inaudible) investigation.

But I think that we do need to expand the search area, I think we need to keep looking and I think we're going to continue using and should AUVs.

BANFIELD: As a pilot when we talk about eyes on, the big question is, is it time to scale back those aircraft searches for floating debris? Is it time to really just focus on the water and pull all those pilots back from sometime dangerous missions, certainly exhaustive missions, and very expensive missions?

KAY: I think you're going to have to at some point, anyway, because the air crews and the aircraft have been operating at surge tempos, 48 days.

They're flying to the outer limits of the hours that they're allowed to fly. They have limitations in their standard operating procedures that give them maximum limits for a week, a month and year flying and they will -- if they're going to be breached, they will have to be specifically authorized to go above and beyond that.

Over and above that, you've got the engineering constraints, you've got the deep servicing that all the aircraft are going to require because of the physical hours that they're actually flying on the search operations. So there will have to be some sort of natural tailback, as you rightly point out. But I think it will be a reset. They'll look at the bigger evidence, the macro evidence, and then they'll go out again.

BANFIELD: Yes. And I think we're somewhere around the time when the reset starts to become a reality. I mean we're at day 48 and still nothing.

Christine Dennison, Michael Kay, thank you as always.

You know, the search for this missing plane is complicated by something very simple, something that you and I don't think anything about day-to-day, and that is garbage. Take a look at all those gyres circling in the oceans around the world. Hundreds of millions of pieces of garbage could be masking what is now a very disperse field of debris if there ever was one. We're going to talk about that challenge in a moment.

(COMMERCIAL BREAK)

BANFIELD: Promising leads quickly turning into false alarms. It seems like a repeating story, doesn't it? Remember this object of interest from only yesterday in the search for Malaysia Airlines 370? You may have heard by now that it isn't connected to the missing plane after all, not at all. Just one of countless objects that wash ashore, become part of the giant swirling vortex of ocean garbage where pieces of a plane, sadly, could simply get lost. Randi Kaye now gives us a rare look at the tons of trash degrading millions of square miles of our oceans and possibly, just possibly, obscuring any trace of MH-370.

(BEGIN VIDEOTAPE)

MARCUS ERIKSEN, 5 GYRES INSTITUTE: Debris that you might see, you know, in our homes, all around our homes. Here's a toy grenade. Here is a paintbrush handle. Here's a toy leg from a baby. Flip-flops.

RANDI KAYE, CNN CORRESPONDENT (voice-over): Not items from a landfill, but from the ocean, more specifically the Indian Ocean gyre, essentially a garbage patch swirling with trash and overflowing with plastic. The massive, rotating current spins counterclockwise. Marcus Eriksen is the director of research for the 5 Gyres Institute in California. He says gyres are like plastic soup.

ERIKSEN: That's typical of what the material looks like.

KAYE: In 2010, he sailed through the Indian Ocean gyre, the same area where search teams are now looking for doomed Flight 370.

ERIKSEN: And what we found there were things like (INAUDIBLE) fishing nets, multi-colored buoys, little fishing buoys like the one that's behind me, lots of buckets and crates, other consumer goods like bottles and bottle caps and bags and forks and knives. There was so much stuff already there. So the aircraft - the debris from the aircraft is blending into all that.

KAYE: Which is one reason why locating the missing plane is such a challenge. Satellite images, once thought to be debris fields, likely just floating garbage. Recently, a Chinese ship, in search of the airplane, came across trash instead. Even sea life can't tell the difference. Fish, sea lions, birds, they all ingest this junk thinking it might be food.

ERIKSEN: You know, I hear this talk about there being 300 plus pieces from the aircraft. There are 300,000 plus pieces of trash already there.

KAYE: The Indian Ocean gyre isn't the only one that exists. There are also two in the Pacific and two in the Atlantic. They form when ocean currents bounce off the continents and create a vortex of swirling water which pulls debris from the shores to the center of the ocean.

KAYE (on camera): The gyre in the Indian Ocean is thought to be about two million square miles. Now keep in mind, the entire United States is just under 4 million square miles. And this garbage patch isn't just huge, it's also on the move, traveling about half a mile per hour or about 12 miles per day. And it may be carrying parts of the plane with it.

ERIKSEN: It's moved away from the crash site. It's moved away maybe 50 to 150 miles by now. And it's dispersed as well. And it's joining the background of other debris.

KAYE: Leaving search teams to play catch-up as they try to track down Flight 370.

Randi Kaye, CNN, New York.

(END VIDEOTAPE)

BANFIELD: One of the more remarkable pieces of information that may emerge from that issue, the ocean gyres, is what those gyres of garbage actually do to bigger pieces of debris. They don't just hide them, they could destroy them. That story is coming up next.

(COMMERCIAL BREAK)

BANFIELD: As many experts as there are looking for the missing plane, it could be the keen eye of someone on land, a beachcomber, that could end up cracking this mystery.

I want to bring in Curt Ebbesmeyer, an oceanographer and president of Beachcombers Alert, to ask more about this.

We just talked about the gyres and the garbage that's out floating in the ocean. We're now several months into this mystery. Is this about the time that we might expect to start seeing debris wash up on land somewhere, Curt?

CURT EBBESMEYER, PRESIDENT, BEACHCOMBERS ALERT: Yes, Ashleigh, this is about the time that the leading edge of a debris field will travel 20 miles per day. So, given 50 days and a thousand miles out is where the searchers had been searching. So I would guess that the debris field should be arriving now.

This -- even though this piece of wreckage or piece of debris were a false lead, I think it's a heads-up that now is the time to be expecting pieces, larger pieces, pieces that stick out of the water. You might see pieces of cushions. You might see, you know, table trays. Most jets are -- have a lot of plastic in them and most plastic floats. And we should be seeing some things starting about now.

BANFIELD: So, I heard Mary Schiavo say this morning on "New Day," and she's formerly with the Department of Transportation, that it might be wise to start deploying brigades of people, whether they be volunteer or military, to actually beachcomb those western edges of Australia. They need some sensitivity training, too, don't they?

EBBESMEYER: Yes, they -- it's very hard to detect what's trash and what's debris. There's just so much material that's deceptive. Like if you're eating a meal and you have a fork on an airplane, well, that plastic fork would be debris, but there's an awful lot of plastic forks that wash up.

So you're talking thousands of miles of shoreline, not just the western shores, but we probably ought to be thinking about some of the southern shores of Australia. So I think a good educational campaign outreach to the public is part of it. So it's a very difficult thing to do but beachcombers, there's many, many of thousands of diligent beachcombers. So getting the word out to them is probably key.

BANFIELD: Not to mention the personal effects that might end up washing ashore.

And, Curt, I - you know, one of the other amazing things that I remember hearing about this is that those gyres turn big pieces of debris into smaller and smaller and smaller pieces of debris that are less detectable. So, you're right, the training that's needed would be remarkable.

Curt, it's always good to talk to you and thank you for your time today.

EBBESMEYER: Thank you, Ashleigh.

BANFIELD: Hopefully the next time it might be on a better note with something else to go on. Thank you. Our thanks to Curt Ebbesmeyer.

So, what happens if Flight 370 is never found? It will go down as one of the world's most enduring mysteries like Amelia Earhart who disappeared on the first around the world fight in June 1937. Or how about Madeleine McCann, that three year old girl who simply vanished in June of '07 on a family vacation in Portugal. It's still a mystery seven years later.

And they've waited 48 days now with hardly any answers to cling to, but hopefully those family members will have something to go on soon or hopefully people will see changes in policy for tracking planes to help searchers and family members so that something like this will never happen again.